Preparation of caprolactam from 6-aminocapronitrile

US5693793A · kind A · utility

Assignee

• BASF SE

Inventors

• Josef Ritz · Ludwigshafen, DE
• Eberhard Fuchs · Bischofswerda, DE
• Guido Voit · Freinsheim, DE
• Gunther Achhammer · Mannheim, DE
• Rolf Fischer · Heidelberg, DE

Key dates

• Filing date: Sep 5, 1996
• Grant date: Dec 2, 1997
• Expiry date: Sep 5, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D201/08
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing caprolactam by cyclization of 6-aminocapronitrile in the presence of water at elevated temperature and in the presence or absence of a catalyst and a solvent, comprises PA1 a) removing from the cyclization reaction effluent ("reaction effluent I") caprolactam and all components boiling higher than caprolactam ("high boilers"), PA1 b) treating the high boilers of stage a) with phosphoric acid and/or polyphosphoric acid at from 200 to 350.degree. C. to obtain a reaction effluent II, and PA1 c) removing caprolactam formed and any 6-aminocapronitrile from reaction effluent II of stage b) to obtain separation from unconverted high boilers and acid used.